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Commit 4aac0a63 authored by Alasdair G Kergon's avatar Alasdair G Kergon Committed by Linus Torvalds
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[PATCH] device-mapper snapshot: barriers not supported 



The snapshot and origin targets are incapable of handling barriers and need to
indicate this.

Signed-off-by: default avatarAlasdair G Kergon <agk@redhat.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 3eaf840e

drivers/md/dm-snap.c

+6 −0
Original line number Diff line number Diff line
@@ -792,6 +792,9 @@ static int snapshot_map(struct dm_target *ti, struct bio *bio, 
	if (!s->valid)

		return -EIO;



	if (unlikely(bio_barrier(bio)))

		return -EOPNOTSUPP;



	/*

	 * Write to snapshot - higher level takes care of RW/RO

	 * flags so we should only get this if we are
@@ -1058,6 +1061,9 @@ static int origin_map(struct dm_target *ti, struct bio *bio, 
	struct dm_dev *dev = (struct dm_dev *) ti->private;

	bio->bi_bdev = dev->bdev;



	if (unlikely(bio_barrier(bio)))

		return -EOPNOTSUPP;



	/* Only tell snapshots if this is a write */

	return (bio_rw(bio) == WRITE) ? do_origin(dev, bio) : 1;

}